1. Field of the Invention
Apparatus and method for producing images of the distribution in three dimensions of photon emitting materials (radioactive pharmaceuticals) in the body including detector, detector support and body support.
2. Description of the Prior Art
Area radiation detectors of the scintillation camera type rotate around the subject containing radioactive material so as to view the radiation from a plurality of angles. Radiation detection information and detector position information are correlated by computer reconstruction to provide images of the distribution of the radioactive material within the body in a variety of views such as transverse or longitudinal slices through the body. Prior art uses one or more scintillation detectors in a rotating ring. The radius of the cylinder described by the moving face of the detector is generally fixed large enough to accommodate a large person. Resolution or image quality of these detection systems deteriorates rapidly as the subject/detector distance increases so that a fixed radius unnecessarily sacrifices image quality in a smaller subject. General Electric Corp. has recently introduced a rotating counterbalanced detector (see enclosed brochure) whose radius of rotation can be adjusted before operation to a smaller cylinder to view the head or a child with shorter subject/detector distance.
However, the shape of the body and the illustrated cantilevered body support are not cylindrical, so that imaging the torso requires setting the radius to allow the detector to clear the support sides which means that when the detector is over the chest, it may be very far from the body surface, causing a loss of image resolution. Further, the geometry of the counterweight support requires a cantilevered body support. The cantilevered body support requires great strength and rigidity of construction, interfering with design for adjustability to smaller bodies and thin construction for transparency to the radiation which must pass therethrough to the detector. The counterbalance mechanism is effective mechanical engineering because the counterweight for the detector head provides rotational balance as well, so that only small uniform force for rotation is required at any angle. Unfortunately, the biological engineering is not as effective, because the rotating counterweight and ring geometry interfere with extending the arms overhead. Arms at the side increase the radius of the cylinder of rotation needlessly and also absorb imaging radiation from the torso.